Hearing aid circuitry typically is powered by 1.3 volt zinc air batteries. Traditionally, the use of such low battery voltages for operating a hearing aid has caused many hearing aids to suffer from a lack of headroom. Headroom defines the difference between the absolute maximum output a hearing aid can produce and the sum of gain and input level. If the gain plus input level exceed this absolute maximum output or ceiling, distortion and poor sound quality result. A higher battery voltage would theoretically permit greater headroom. Recently, higher voltage hearing aid batteries have become available, for example, a 3.8 volt. However, since most hearing aid circuits have been designed to operate on 1.3 volts, only some portions of the hearing aid circuit are designed to operate at higher voltages and take advantage of this increased voltage level. However, the circuits of a hearing aid can be redesigned to capitalize on this higher voltage, but modifications may be expensive and time consuming. For these and other reasons there is a need for the present invention.